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Thu Jul 11, 2019, 07:51 PM

Gay black woman classical singer upsetting evolutionary doctrine by discussing insects.

The news item I'll discuss is here: The biologist using insect eggs to overturn evolutionary doctrine (Giorgia Guglielmi, Nature 571, 24-26 (2019))

I believe the news item is open sourced, but I'll excerpt it anyway, before referring to excerpts and graphics in Dr. Extatour's paper in the same issue of Nature, which is probably not open sourced. That paper is this one: Insect egg size and shape evolve with ecology but not developmental rate (Extatour, Church, et al, Nature 571, 58–62 (2019))

Excerpts from the News Item:

By the spring of 1998, Cassandra Extavour had spent more than two years failing to get her PhD off the ground. She had moved from her native Toronto in Canada to a pioneering laboratory in Madrid, where she was trying to engineer the eggs of fruit flies to have two different genetic make-ups. But she hit hurdle after hurdle, and nobody in the lab could help. If she couldn’t make the flies within the next few months, she would have to quit the project.

As she sat with her adviser and went through the dozens of unsuccessful tests she had done, they came up with one last strategy to make the flies using a different gene variant. Her adviser reassured her that it wouldn’t have any unwanted effects, but couldn’t point to any hard data. Even with time running out, Extavour was unwilling to take his word for it. She embarked on a months-long series of experiments to prove to herself that the gene did what he said. In the process, she built her own tools to ask a question that nobody had addressed before...

...Two decades later, Extavour is still pursuing original research questions and overturning convention as she investigates some of the most fundamental aspects of animal development. In her lab at Harvard University in Cambridge, Massachusetts, Extavour wants to understand how single-celled entities blossomed into multicellular organisms during evolution, and how the intricate bodies of such organisms can develop from cells that all have the same genetic blueprint...

...Whereas most researchers work with only a handful of well-studied animals, such as fruit flies and mice, Extavour’s success comes from her penchant for less-ubiquitous lab critters, such as sand fleas and crickets. Typical model organisms harbour just a fraction of the diversity found in nature, so alongside the usual suspects, she examines a wide range of animals...


...Two decades later, Extavour is still pursuing original research questions and overturning convention as she investigates some of the most fundamental aspects of animal development. In her lab at Harvard University in Cambridge, Massachusetts, Extavour wants to understand how single-celled entities blossomed into multicellular organisms during evolution, and how the intricate bodies of such organisms can develop from cells that all have the same genetic blueprint. “I have never heard of a problem that I thought was more interesting than that,” she says.

Extavour’s curiosity and rigorous thinking have led her to test, and in some cases disprove, widely accepted hypotheses about development and evolution. She upended the leading theory of how most animals generate the precursors of eggs and sperm1, and in a Nature paper this week, she and her team have cracked a long-standing question about the astonishing diversity of insect eggs2.

Just as an orchestra produces a sublime concerto, a suite of meticulously balanced genes controls an organism’s form and function. Extavour appreciates this better than most: she juggles science alongside a side career as a soprano. Even while rewriting scientific doctrine, she performs with professional ensembles in Boston and has appeared in operas and choirs from Canada to Spain.

Whereas most researchers work with only a handful of well-studied animals, such as fruit flies and mice, Extavour’s success comes from her penchant for less-ubiquitous lab critters, such as sand fleas and crickets. Typical model organisms harbour just a fraction of the diversity found in nature, so alongside the usual suspects, she examines a wide range of animals that help to reveal which genetic tools evolution most commonly uses.

She has also emerged as a champion for diversity and inclusivity, having experienced racism and prejudice as a gay black woman in science. Even after becoming a tenured professor, she still encounters people who assume she doesn’t belong. She spends time mentoring students from under-represented groups and helped to found the Pan-American Society of Evolutionary Developmental Biology, which unites hundreds of researchers across the Americas...

...Music has been in Extavour’s life since she was in the cradle. Science came much later, almost by accident.

Her father, who moved to Canada from Trinidad and Tobago in the 1960s, was a broadcast technician and percussionist. He played in concerts and used to practise in the basement of their three-bedroom house in downtown Toronto with his four kids. The first instrument Extavour played was a steel drum. In elementary school, she learnt to read music and taught herself to play the flute, borrowing music scores from the library. At university, Extavour played in orchestras and duos, and took up classical singing...

...A high-school friend got her interested in the workings of the brain, and by the end of her undergraduate studies, she had found her way to molecular genetics. At the University of Toronto, Extavour traded off science and music, landing her first professional singing gig with a baroque orchestra and working a summer job as an administrative assistant for developmental biologist Joseph Culotti. There, Extavour heard for the first time about the problem...


Dr. Extavour in her office:



As promised, some brief excerpts from her paper beginning with the open abstract...:

Over the course of evolution, organism size has diversified markedly. Changes in size are thought to have occurred because of developmental, morphological and/or ecological pressures. To perform phylogenetic tests of the potential effects of these pressures, here we generated a dataset of more than ten thousand descriptions of insect eggs, and combined these with genetic and life-history datasets. We show that, across eight orders of magnitude of variation in egg volume, the relationship between size and shape itself evolves, such that previously predicted global patterns of scaling do not adequately explain the diversity in egg shapes. We show that egg size is not correlated with developmental rate and that, for many insects, egg size is not correlated with adult body size. Instead, we find that the evolution of parasitoidism and aquatic oviposition help to explain the diversification in the size and shape of insect eggs. Our study suggests that where eggs are laid, rather than universal allometric constants, underlies the evolution of insect egg size and shape.

Insect eggs are a compelling system with which to test macroevolutionary hypotheses. Egg morphologies are extraordinarily diverse8, yet they can be readily compared across distant lineages using quantitative traits. Changes in egg size have been studied in relation to changes in other aspects of organismal biology9, including adult body size10,11,12, features of adult anatomy13 and offspring fitness through maternal investment14. Eggs must also withstand the physiological challenges of being laid in diverse microenvironments, including in water, air, or inside plants or animals15. Furthermore, because the fertilized egg is the homologous, single-cell stage in the lifecycle of multicellular organisms, egg size diversity is relevant to the evolution of both cell size and organism size8,14.

Three classes of hypotheses have been proposed to explain the evolution of egg size and shape. The first suggests that geometric constraints due to the physical scaling of size and shape explain the diversity of egg morphology13,16,17,18,19. The second suggests that there is an interaction between egg size and the rate of development20,21,22. Finally, the third suggests that the diversification of size and shape is a response to ecological or life-history changes10,13,15,23...

...Using custom bioinformatics tools, we assembled a dataset of 10,449 published descriptions of eggs, comprising 6,706 species, 526 families and every currently described extant hexapod order24 (Fig. 1a and Supplementary Fig. 1). We combined this dataset with backbone hexapod phylogenies25,26 that we enriched to include taxa within the egg morphology dataset (Supplementary Fig. 2) and used it to describe the distribution of egg shape and size (Fig. 1b). Our results showed that insect eggs span more than eight orders of magnitude in volume (Fig. 1a, c and Supplementary Fig. 3) and revealed new candidates for the smallest and largest described insect eggs: respectively, these are the parasitoid wasp Platygaster vernalis27 (volume = 7 × 10−7 mm3; Fig. 1c) and the earth-boring beetle Bolboleaus hiaticollis28...


Figure 1:



The caption:

a, Eggs are plotted in a morphospace defined by volume (mm3) and aspect ratio (unitless) on a log scale. Points are coloured by clades as shown in b. b, Relationships are shown according to a previous study25, one of the backbone phylogenies used in this study. Numbered points correspond to six eggs shown in c. c, Eggs selected to show a range of sizes and shapes, arranged by aspect ratio27,28,48,49,50,51. d, Size and shape are described using six features, calculated as shown.


o test these hypotheses about the physical scaling of size and shape, we began by modelling the evolutionary history of each morphological trait. This allowed us to determine whether distributions of extant shape and size have been shaped by phylogenetic relationships. For egg volume, aspect ratio, asymmetry and angle of curvature (Fig. 1d), we compared four models of evolution: Brownian motion, Brownian motion with evolutionary friction (Ornstein–Uhlenbeck), Brownian motion with a decreasing rate of evolution (early burst) and a non-phylogenetic model of stochastic motion (white noise). We found that models that accounted for phylogenetic covariance fit our data better than a non-phylogenetic model (white noise); in other words, the morphology of insect eggs tends to be similar in closely related insects (Supplementary Table 5).


Figure 2:



The caption:

a–c, Hypothesized relationships between size and shape: larger eggs are proportionally wider (a, solid line); larger eggs are proportionally longer (b, dotted line); shape and size scale isometrically (c, dashed line). d, Each hypothesis predicts a different scaling exponent—the slope of the regression between the log-transformed length and log-transformed width. Lines are as in a–c. e, Egg length and width plotted in log–log space. The dashed line represents a hypothetical 1:1 relationship (c). Solid lines are clade-specific phylogenetic generalized least-squares regressions; points are randomly selected representatives per genus. n numbers (genera): Palaeoptera, n = 104; Polyneoptera, n = 262; Condylognatha, n = 202; Hymenoptera, n = 356; Neuropteroidea, n = 265; Amphiesmenoptera, n = 76; Antliophora, n = 199. f, The distribution of scaling exponents from phylogenetic generalized least-squares regressions, calculated over the posterior distribution. White lines, boxes, bars and dots represent median, 25–75th percentiles, 5–95th percentiles and outliers, respectively. Asterisks indicate a significant relationship (P < 0.01, exact values are shown in Supplementary Table 6) and double daggers indicate that the relationship is not distinguishable from isometry (P > 0.01, exact values are shown in Supplementary Table 7). n = 100 phylogenetic generalized least-squares regressions. Colours correspond to Fig. 1b.


Figure 3:



The caption:

a, Mature eggs undergo embryonic development, hatch and grow into adults. b, Egg volume (mm3) compared to duration of embryogenesis, defined as time from egg laying to hatching (hours), adjusted for incubation temperature. When phylogeny is accounted for, there is no significant relationship. c, Egg volume (mm3) compared to adult body volume, calculated as body length cubed (mm3). Dashed line represents a hypothetical 1:1 relationship (isometry). Solid lines are clade-specific phylogenetic generalized least-squares regressions; points are family- or order-level average egg size and median adult size. n numbers (family- or order-level averages): Palaeoptera, n = 15; Polyneoptera, n = 31; Condylognatha, n = 36; Hymenoptera, n = 44; Neuropteroidea, n = 36; Amphiesmenoptera, n = 31; Antliophora, n = 39. d, The distribution of scaling exponents from phylogenetic generalized least-squares regressions. White lines, boxes, bars and dots represent median, 25–75th percentiles, 5–95th percentiles and outliers, respectively. Asterisks indicate a significant relationship (P < 0.01, exact values are shown in Supplementary Table 12) and double daggers indicate that the relationship is not distinguishable from isometry (P > 0.01, exact values are shown in Supplementary Table 13). n = 100 phylogenetic generalized least-squares regressions. Colours correspond to Fig. 1b.




The caption:

a, Two modes of oviposition ecology: laying eggs within an animal host (orange; for example, parasitoid wasps), and in water (blue; for example, mosquitoes). Other oviposition substrates (for example, terrestrial or within plants) are shown in grey. b, Ancestral state reconstruction of oviposition mode reveals both evolved multiple times (see Supplementary Figs. 17, 18). c–f, The distribution of egg features, coloured by ecology. c, Volume (mm3; shown on a log scale). d, Aspect ratio (unitless; shown on a log scale). e, Asymmetry (unitless). f, Angle of curvature (degrees). Asterisks indicate that the model that accounts for ecology fits the data better than a non-ecological model (Ornstein–Uhlenbeck model with multiple optima, ∆AICc > 2, exact values are shown in Supplementary Tables 14–19).


The conclusion to the paper:

a, Two modes of oviposition ecology: laying eggs within an animal host (orange; for example, parasitoid wasps), and in water (blue; for example, mosquitoes). Other oviposition substrates (for example, terrestrial or within plants) are shown in grey. b, Ancestral state reconstruction of oviposition mode reveals both evolved multiple times (see Supplementary Figs. 17, 18). c–f, The distribution of egg features, coloured by ecology. c, Volume (mm3; shown on a log scale). d, Aspect ratio (unitless; shown on a log scale). e, Asymmetry (unitless). f, Angle of curvature (degrees). Asterisks indicate that the model that accounts for ecology fits the data better than a non-ecological model (Ornstein–Uhlenbeck model with multiple optima, ∆AICc > 2, exact values are shown in Supplementary Tables 14–19).


From the conclusion of the news item:

Extavour, who didn’t tell colleagues about her sexual orientation until her postdoc years, says that she can appreciate how students who come out as lesbian, gay, bisexual, transgender or queer might feel isolated. Rainbow-flag stickers on the doors of her office and laboratory spaces signal to students that everyone is welcome. “Being out at work is important, because it allows young people to see that it’s possible to be gay and out and alive and have a job,” she says.

Extavour learnt from her family that she should not let other people’s prejudices define what she could and could not do; they also inspired her to set her own standards for how well she should do it. And those who know her say that Extavour aims high. “She’s motivated by big questions,” Dunn says. “She has her eyes on the horizon.”


It would be interesting to hear the orange idiot have one of his fellow racists read to him on Fox News and use it to expound to his fellow racists how ignorant barely literate frat boy White Men who speak like 4th graders are superior to gay, black women.

Well, perhaps not interesting, one can only spend a limited amount of time being interested in a functional idiot, but it would be telling.






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